<!DOCTYPE html>
<html lang="zh">
<head>
	<meta charset="UTF-8" />
	<meta name="viewport" content="width=device-width, initial-scale=1.0" />
	<meta http-equiv="X-UA-Compatible" content="ie=edge" />
	<title>Document</title>
</head>
<style type="text/css">
	#dv {
		width: 100px;
		height: 100px;
		background-color: red;
	}
</style>
<body>
	<div id="dv">
		123
	</div>
</body>
</html>